Seal between two parts, one of which is rotatable in relation to the other

ABSTRACT

A seal for at least a pair of relatively rotatable members for preventing lubricant from leaking from a lubricant chamber to the space outside the lubricant chamber comprising a first seal element having a sealing portion mounted on the rotatable member and adapted to bear against a contact surface on the other member to form a primary seal area supporting the lubricant chamber from the space outside the lubricant chamber characterized by the first seal element mounted on the rotatable member having a bore therein forming a duct connecting the lubricant chamber with the space outside the lubricant chamber, said bore being located radially to one side of the primary seal area so that lubricant bypassing the primary seal area will be discharged through the bore to the lubricant chamber under the influence of centrifugal force.

United States Patent Malmstrom 51 Aug. 22, 1972 [54] SEAL BETWEEN TWOPARTS, ONE OF WHICH IS ROTATABLE IN RELATION [22] Filed: Nov. 21, 1969[21 Appl. No.: 878,616

[30] Foreign Application Priority Data Nov. 21, 1968 Sweden ..15827/68[52] US. Cl. ..277/25, 277/75, 277/82, 308/187.1

[51] Int. Cl. ..F16j 15/16 [58] Field of Search ..277/81, 82, 89, 95,75, 25, 277/3, 15, 133; 308/187.1

FOREIGN PATENTS OR APPLICATIONS 170,393 12/1959 Sweden ..308/l87.11,553,413 12/1968 France ..277/25 Primary Examiner-Robert I. SmithAtt0rney Howson and Howson 7] ABSTRACT A seal for at least a pair ofrelatively rotatable members for preventing lubricant from leaking froma lubricant chamber to the space outside the lubricant chambercomprising a first seal element having a sealing portion mounted on therotatable member and adapted to bear against a contact surface on theother member to form a primary seal area supporting the lubricantchamber from the space outside the lubricant chamber characterized bythe first seal element mounted on the rotatable member having a boretherein forming a duct connecting the lubricant chamber with the spaceoutside the lubricant chamber, said bore being located radially to oneside of the primary seal area so that lubricant bypassing the primaryseal area will be discharged through the bore to the lubricant chamberunder the influence of centrifugal force.

9 Claims, 7 Drawing Figures IIIIIMIIIIIIIIIII I PATENTED M1822 I972 l 1Mp0 I mvcuron; SVEN ERIK MALMSTRUM ,WWW

, I ATTYS.

SEAL BETWEEN TWO PARTS, ONE OF WHICH IS ROTATABLE IN RELATION TO THEOTHER The present invention relates to a seal between two parts, one ofwhich is stationary and the other rotatable. The object of the seal isto prevent oil on the so called oil side from leaking to the other side,the air side. In the main, the seal comprises two components, one ofwhich is preferably provided with a rubber lip, and the other with asealing wall, bearing against a contact surface facing the said lip. Thecomponents form a primary sea] at the said contact surface which sealthus separates the oil side from the air side. Seals of this design thusinclude the majority of types of both radial and axial seals of lipdesign most commonly in use. The features distinguishing a sealaccording to the invention from seals known per se, are as follows:

Behind the primary seal, as seen from the oil side, the rotatable parthas been bored through, thus forming a duct connecting the air side withthe oil side. The hole is so located that oil, possibly leaking throughto the air side under the influence of the centrifugal force, will bethrown back to the oil side.

With the object of specifying the invention more in detail, a number ofrepresentative embodiments are described below in conjunction with theattached drawmg.

FIGS. 1-7 show cross sections of sealing arrangements adapted to seal abearing house against leakage of oil contained therein.

In FIG. 1, the numeral 11 denotes a shaft, 12 a ball bearing, and 13, abearing house. In the sealing case illustrated in FIG. 1, the shaft 11is stationary whereas the housing revolves. The numeral 14 denotes acuff type packing ring of rubber fitted into the bearing house bypressure. The packing ring is provided with a sheet metal stifi'ener 15.-A sealing lip 16 bears against the shaft 11 with its sealing edge 17.For the purpose of compensating any possible setting in the rubber andin order to ensure constant pressure, the lip 16 is encircled by a coilspring 18. A duct 19 through the lip 16 forms a connection between theoil side and the air side. The duct or bore 19 is preferably of a sizelarger than about 0.5 millimeters and less than about 4 millimeters. Thepacking ring 14 is also fitted with an additional sealing lip 110 whichbears against the shaft 11 and forms a secondary sealing arrangement. Anannular space 111, connected with the oil side through the duct 19, isthus formed between the lip 110 and the sealing edge 17. The sealaccording to FIG. 1 functions as follows:

Oil possibly escaping past the sealing edge 17 will be thrown outwardsby the revolving sealing lip 16 and then follow the tapered wall 112, inthe direction of the duct 19, where it is thrown back into the oil sideby centrifugal force.

FIG. 2 shows a somewhat different design in which the shaft 21 is therotating component, whereas the bearing house 23 is stationary. Into thebearing house has been pressed a packing ring 24 of rubber, stiffened bymeans of a metal ring 25. The inside portion of the packing ring isprovided with a cylindrical inwarddirected lip 26, the edge 27 of whichbears against a tapered sealing surface 28 of a sheet metal ring 210embracing the shaft and likewise provided with a hole 29. The embodimentaccording to FIG. 2 is also equipped with a secondary seal whichincludes a sealing lip 211' bearing against the shaft. On rotation ofthe shaft, and consequently also the sheet metal ring 210, any oilpossibly leaking out, will be thrown back to the oil side by centrifugalforce through the hole 29.

FIG. 3 illustrates a sealing arrangement differing from that shown inFIG. 2 by the sheet metal ring 210 having been substituted by a rubberring 310 mounted on the shaft 31 which ring, by means of aninwarddirected lip 36 bears against the cylindrical surface 38 of aprofiled sheet metal ring 34, fitted by pressure into the bearing house33. In the intermediate portion between the rubber ring 31 and the lip36 has been formed a duct 39, the object of which similarly to theembodiments described above is to return any oil possibly having leakedpast the primary seal between the lip 36 and the cylindrical surface 38.A flange 37, extending from the cylindrical surface 38, prevents leakingoil from coming into contact with the shaft 31.

The sealing arrangement according to FIG. 4 includes a packing ring ofrubber 44, and a metal ring 410, press-fitted on to the shaft 41including in principle, two funnel-shaped portions 42 and 46 facing eachother. At the intermediate portion between these two tapered parts 42and 46 there is provided a punched hole 49. With its free edge, thefunnel-shaped portion 46 bears against the internal annular and planelimiting surface 47 of the packing ring and forms a primary seal at thispoint. Possibly leaking oil will be thrown outwards by centrifugalforce, and is returned to the oil side through the hole 49. Theembodiment according to FIG. 4 is also provided with a secondary seal411, the

object of which is to prevent dirt and foreign particles from passingfrom the air side to the oil side through the hole 49.

The seal according to FIG. 5 differs from the above (FIG. 4) only by thepacking ring 54 being provided with a sealing lip 56 which, by means ofan outwardly directed sealing edge 57, forms a primary seal against acylindrical surface 58 of a sheet metal ring 510. This latter ring isalso provided with a hole 59, located radially outside the sealingsurface 58. The idea of this feature is to increase the centrifugalforce, and thus create a more efficient throwing effect in the event ofa possible leaking of oil.

The sealing arrangement according to FIG. 6 comprises principally arubber disc 64 pressed into the bearing house, the said disc beingadapted to bear against a sheet metal ring 610 along circular lines andpossibly be composed of a number of tapered 62 a and b, and 66 a and b,facing each other. The holes 69 a and b have been bored through thetapered rings 66 a and b. The purpose of these holes is identical withthat already described in connection with FIGS. 1 5, i.e., to returnleaking oil by centrifugal force to the oil side of the seal in theevent of a leakage.

FIG. 7, finally, illustrates an arrangement comprising two rubber rings,one of which, 74 a, is fitted by pressure to the shaft 71, and theother, 74 b, is inserted into the bearing house 73 under tension. Twoidentical metal washers, 72 a and 72 b, have been pressed into groovesprovided in the respective rubber rings 74 a and 74 b and 72 a with itsinner portion, and 72 b with its outer portion. The metal rings arecomposed of an external and an internal annular part, joined to a one ofsaid seal elements.

tapered portion. In its tapered part, the metal ring 72 a is providedwith'a hole 79 having the same purpose as that described above inconnection with the other embodiments. Jointly with the grooves 78 a and78 b in the packing rings 74 a and 74 b, the outer and inner annularportions, respectively, of the metal rings 72 a and 72 b, formlabyrinths or possibly friction seals. In the embodiments describedabove, the bore or duct 29 of FIG. 2, 39 of FIG. 3, 49 of FIG. 4,59 ofFIG. 5, 69 of FIG. 6, and 79 of FIG. 7 are all preferably in the samesize range as that set forth in connection with FIG. 1; that is, of asize larger than about 0.5 millimeters and less than about 4millimeters.

What is claimed is: v

l. A seal adapted to be mounted between a shaft member engageable in ahousing member, the mem-' 'bers being mounted for relativerotation,comprising a first seal element mounted on one of said members, a

second seal element, said sealing elements combining to define alubricant chamber and another chamber connected at its radiallyoutermost portion to said lubricant chamber, at least a portion of saidlubricant chamber being disposed radially outwardly of said otherchamber, said chambers being connected by a bore of a size which islarger than about 0.5 millimeters and less than bout 4 millimeters incross section whereby lubricant from said lubricant chambers which maybypass said seal elements to said other chamber will be dischargedthrough said bore to said lubricant chamber under the influence ofcentrifugal force.

2. A seal as claimed in claim 1 wherein said seal is a resilient membermounted in the housing having a radial lip comprising one of said sealelements engaging the shaft and an ofiset lip comprising the other sealelement projecting angularly from said radial lip having a sealing edgeengaging the shaft at an area axially removed from said radial lip anddefining therebetween the other chamber and wherein said bore isdisposed in 3. A seal as claimed in claim 2 including a coil springmaintaining one of said sealing edge in engagement with the shaft.

4. A seal as claimed in claim 1 wherein said first seal elementcomprises a resilient member mounted in the housing having a sealing lipengaging the shaft and said second seal element comprises a metallicring mounted on said shaft engaging said first seal element to define lA therebetween the other chamber and wherein said bore I is disposed atthe apex between said funnel-shaped por- T tions. I

'6. A sea] as claimed in claim 4 wherein said second sealing elementcomprises a metallic ring of zig-zag cross" section and including aplurality of bores in said metallic ring. 7. A seal as claimed in claim4 wherein said first seal comprises a resilient ring member. havingafirst lip engaging the shaft and a second radially inwardly directed flip portion and wherein said second seal element comprises a metallicring mounted on the shaft having a 7 generally cylindrical portionengaging said sealing lip and formed to define said other chambertherebetween n h 'th boresd's d' 'd e i rin.

a E as laime in claim 1 ereir i firsteal elements consists of a profiledsheet metal ring mounted in the housing having a cylindrical surfacespaced from the shaft and said second seal element A comprises aresilient rubber ring mounted on the shaft having a sealing lip engagingsaid cylindrical surface and wherein said bore is disposed at thejuncture of said sealing lip and said sealing ring. I

9. A seal as claimed in claim 1 including a pair of rubber rings mountedin the housing and on the shaft respectively radially spaced apart todefine an annular space therebetween, and wherein each of said rings isprovided with at least one circumferentially extending groove andwherein said second seal element comprises at least one metallic ringengaging in the grooves of the rings, said bore being disposed in saidmetallic ring in the annular space between said resilient rings.

' UNITED STATES PATENT OFFICE CERTEFICATE 9F CGRRECTEGN,

Patent No 3 ,685 ,838 Date d A'ugus t 22 1972 Inventor(s) SVEN-ERIKMALMS TROM It is certified that error appears in the above-identifiedpatent and that said Letters Patentare hereby corrected as shown below:

Column 2, line 52; "tapered 623" should read '--tapered rings 62a Signedand sealed this 10th day of Juiy'fi'l 973.

(SEAL) Attest: V I

EDWARD M.FLETCHER,JR. Rene Tegtmeyer Attesting Offieef A i gCommlssloner of Patents FORM P0-1050 (IO-6 USCOMM-DC 60376-P59

1. A seal adapted to be mounted between a shaft member engageable in ahousing member, the members being mounted for relative rotation,comprising a first seal element mounted on one of said members, a secondseal element, said sealing elements combining to define a lubricantchamber and another chamber connected at its radially outermost portionto said lubricant chamber, at least a portion of said lubricant chamberbeing disposed radially outwardly of said other chamber, said chambersbeing connected by a bore of a size which is larger than about 0.5millimeters and less than bout 4 millimeters in cross section wherebylubricant from said lubricant chambers which may bypass said sealelements to said other chamber will be discharged through said bore tosaid lubricant chamber under the influence of centrifugal force.
 2. Aseal as claimed in claim 1 wherein said seal is a resilient membermounted in the housing having a radial lip comprising one of said sealelements engaging the shaft and an offset lip comprising the other sealelement projecting angularly from said radial lip having a sealing edgeengaging the shaft at an area axially removed from said radial lip anddefining therebetween the other chamber and wherein said bore isdisposed in one of said seal elements.
 3. A seal as claimed in claim 2including a coil spring maintaining one of said sealing edge inengagement with the shaft.
 4. A seal as claimed in claim 1 wherein saidfirst seal element comprises a resilient member mounted in the housinghaving a sealing lip engaging the shaft and said second seal elementcomprises a metallic ring mounted on said shaft engaging said first sealelement to define therebetween the other chamber and wherein said boreis disposed in said metallic ring.
 5. A seal as claimed in claim 4wherein said metallic ring includes two funnel-shaped portions and saidbore is disposed at the apex between said funnel-shaped portions.
 6. Aseal as claimed in claim 4 wherein said second sealing element comprisesa metallic ring of zig-zag cross section and including a plurality ofbores in said metallic ring.
 7. A seal as claimed in claim 4 whereinsaid first seal comprises a resilient ring member having a first lipengaging the shaft and a second radially inwardly directed lip portionand wherein said second seal element comprises a metallic ring mountedon the shaft having a generally cylindrical portion engaging saidsealing lip and formed to define said other chamber therebetween andwherein the bore is disposed in said metallic ring.
 8. A seal as claimedin claim 1 wherein said first seal elements consists of a profiled sheetmetal ring mounted in the housing having a cylindrical surface spacedfrom the shaft and said second seal element comprises a resilient rubberring mounted on the shaft having a sealing lip engaging said cylindricalsurface and wherein said bore is disposEd at the juncture of saidsealing lip and said sealing ring.
 9. A seal as claimed in claim 1including a pair of rubber rings mounted in the housing and on the shaftrespectively radially spaced apart to define an annular spacetherebetween, and wherein each of said rings is provided with at leastone circumferentially extending groove and wherein said second sealelement comprises at least one metallic ring engaging in the grooves ofthe rings, said bore being disposed in said metallic ring in the annularspace between said resilient rings.